Anti-vapor lock device



Dec. 6, 1960 H. R. ll-lsl-IER 2,963,013

ANTI-VAPOR LOCK DEVICE Filed 001;. 24, 1957 United States PatentffOtlice 2,963,013 ANTI-VAPOR LoCK DEVICE `I-arold R. Fisher, Mount Prospect, Ill., assiguor to Borgu'ner Corporation, Chicago, Ill., a corporation of nois Filed Oct. 24, 1957, Ser. No. 692,085

9 Claims. (Cl. 123-136) This invention relates to a fuel supply system for an internal combustion engine and particularly to a device for preventing vapor lock in such a fuel supply system.

It is well known that in the operation of an internal combustion engine, having a fuel pump and a carburetor, a vapor lock sometimes occurs in the fuel pump which prevents fuel from reaching the carburetor in sufficient quantity to satisfy engine demand. This condition usually occurs in automotive vehicles when the temperature of thel vehicle engine and fuel pump is relatively high.

In conventional fuel pump design, the volume of fuel pumped is usually approximately 30 times the volume required to satisfy engine demand. Such a pump, therefore, can pump a volume of fuel vapor that is up to 29 times the volume of liquid fuel required by the engine. In the event that the temperature of the fuel pump is su'iciently high to cause a vaporization of the liquid fuel in excess of this amount, so that the vapor to fuel ratio exceeds 29 to l, a vapor lock occurs and insufficient fuel reaches the carburetor to satisfy the engine demand.

It is an object of the present invention to provide a device for preventing vapor lock in the fuel pump or carburetor for a fuel supply system of an internal combustion engine.

It is another object to provide a device for cooling the fuel supplied to a fuel pump for an internal combustion engine, for thereby preventing vapor lock in the fuel pump and carburetor.

It is an additional object to provide a cooling device in the form of a coil having a capillary or small diameter tube extending throughout the length thereof with one end of the tube open to the fuel supply line and the other end of the tube connected to the intake manifold or carburetor of an internal combustion engine.

It is still another object to provide a cooling coil in the fuel supply line for an internal combustion engine in which a portion of the fuel supplied to the engine is allowed to evaporate within the coil, thereby cooling the fuel surrounding the coil and preventing a vapor lock in the supply system of the engine.

The invention consists of the novel constructions, arrangements, and devices to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will appear from the following description of preferred forms of the invention, illustrated with reference to the accompanying drawings, wherein:

Fig. l is a diagrammatic illustration of a fuel supply system for an` internal combustion engine;

Fig. 2 is an enlarged sectional View of the cooling device of the present invention;

Fig. 3 is a sectional view of a modified construction of the cooling device illustrated in Figure 2; and

Fig. 4 is a view taken on line 4-4 of Fig. 3.

Like characters of reference designate like parts in .the several views.

Patented Dec. e, 1960 Referring now to Figure 1, there is illustrated an internal combustion engine 10 for an automotive vehicle; Fuel is supplied to the engine 10 by a fuel supply system which comprises an intake manifold 11, a carburetor 12, a fuel pump 13, and a fuel tank 14. The intake manifold 11 is connected to the 'carburetor 12 by means of a conventional air passage 1S. The carburetor 12 is connected to the fuel pump 13 by means of a fluid conduit 16, and the fuel pump 13 is connected to the gas tank 14 by means of a fluid conduit 17. A cooling device 18 of the present invention is disposed in the fuel line 17.

Referring now to Figure 2, the device 1S comprises a cylindrical casing 19 having a longitudinally extending fuel passage 20 therein and a coil 21 disposed within the passage 20. The coil 21 has a capillary or small diameter tube 22 extending throughout the length thereof. The casing 19 is threaded on its interior at one end of the fuel passage 20 and is adapted to receive a threaded cap 23. The cylindrical casing 19 also is formed with an extended end portion 24 which is threaded on its ex` terior for attaching the casing 19 to the fuel pump 13. The cap 23 is formed with a fuel inlet port 25 opening into the fuel passage 20 and a port 26 opening into the capillary tube 22 of the coil 21. The other end of the capillary tube 22 opens into the passage 2t). The casing 19 also is formed with a fuel outlet port 27 extending through the end portion 24. The port 25 is connected to the gas tank 14 by means of the conduit 17. The port 26 is connected to the intake manifold 11 of the engine 10 by means of a conduit 28. The fuel supply system illustrated in Figure lalso may be provided with a thermostatic element such as a bimetal strip 29 disposed in the conduit 28 and effective to cut off the passage of fuel vapor from the cooling coil 21 to the intake manifold 11.

In operation, the cooling device 18 preferably is attached directly to the fuel pump 13. The fuel pump 13 is driven by the vehicle engine 10 and draws liquid fuel from the gas tank 14 through the fluid conduit 17. The fuel passes from the conduit 17 through the port 25 into the passage 20 Where it flows around the coil 21 and through the outlet port 27 into the fuel pump 13. From the fuel pump 13, the fuel flows through the conduit 16 to the carburetor 12 where it is Vaporized and mixed with air, and the fuel-air mixture passes through the passage 15 into the intake manifold 11.

A pressure exists in the intake manifold 11 which is less than atmospheric pressure, i.e. a partial vacuum. This partial vacuum in the manifold 11 causes a portion of the fuel in the passage 20 to ilow into the capillary tube 22 where it is vaporized and the fuel vapor passes through the conduit 28 into the manifold 11. Vaporzation of the fuel within the capillary tube 2l) absorbs heat from the coil 21 and from the fuel flowing around the coil 21. Removal of heat energy from the fuel around the coil 21 reduces its temperature before passing through the port 27 into the fuel pump 13. The fuel passing to the pump 13 of a reduced temperature is less likely to vaporize within the fuel pump 13 and is consequently less likely to produce a vapor lock in the fuel supply system. This cooling effect also would allow the use of more volatile fuels.

A bimetallic element 29 may be included in the conduit 28 which is adapted to cut off or partially cut off the passage of vaporV through the coil 22 and conduit Z8 at low engine temperatures. Alternatively, the element 29 may be omitted from the conduit 28 with the result that a richer mixture of fuel and air is supplied to the intake manifold 11 at low engine temperatures. This feature may be desirable, particularly during very cold weather.

Referring now to Figure 3, there is illustrated a modified construction 30 of the cooling device 18 which in' cludes a thermostatic element 3-1 built into the cap 23 which is effective to cut off the capillary tube 22 at low engine temperatures when cooling of the fuel is not necessary.

There has been provided by this invention a device adapted to be inserted in the fuel supply system of an internal combustion engine for cooling the fuel supplied to the fuel pump and thereby preventing a vapor lock within the fuel pump.

While I have described my invention in connection with one specific embodiment thereof, it is to be understood that this is by way of illustration and not by way of limitation and the scope of my invention is defined solely by the appended claims which should be construed as broadly as the prior art will permit.

I claim:

l. In a fuel supply system for an internal combustion engine having an air intake manifold, the combination of fuel supply means including a fuel conduit for supplying liquid fuel to the engine, and a cooling coil disposed within the fuel conduit and having a small diameter bore extending therethrough with one end of the coil being connected to the air intake manifold and the other end of said coil opening into said fuel conduit whereby a portion of the fuel supplied to the engine is allowed to evaporate within said coil so as to cool the remainder of the liquid fuel passing through said fuel conduit and thereby prevent a vapor lock within the fuel supply system.

2. In a fuel supply system for an internal combustion engine having an air intake manifold and a carburetor, the combination of a fuel supply tank, a fuel pump for .pumping liquid fuel to the carburetor, a fuel supply conduit interconnecting said tank and said pump, and an .evaporating coil disposed in said fuel supply conduit and Connected at one end to the intake manifold and opening at its other end into said fuel supply conduit to receive fuel therefrom, said evaporating coil being effective to evaporate a portion of the liquid fuel flowing through said supply conduit and thereby reduce the temperature of the remainder of the fuel passing through said fuel supply conduit.

3. In a fuel supply system having an intake manifold a cooling device comprising a casing portion having a longitudinally extending fuel passage therethrough, and an evaporating coil disposed inside of said fuel passage and having a small diameter bore therethrough open at one end to receive fuel from the passage, the other end of said coil adapted to be connected to said intake manifold said coil being effective to evaporate therein a portion of the liquid fuel passing through the passage and 4thereby lower the temperature of the remainder of the -fuel passing through said passage.

4. In a fuel supply system for an internal combustion engine, the combination of fuel supply means including means defining a source of vacuum, a fuel conduit through which liquid fuel flows to the engine and having a portion of enlarged inside diameter, and a cooling coil of relatively small diameter contained within said enlarged portion and being open at one end thereof to said conduit, the other end of said coil adapted to be connected to said vacuum source means whereby fuel flows into the coil and vaporizes therein and cools the coils and thereby the remainder of the fuel passing to the engine.

5. In a fuel supply system for an internal combustion 6 engine having an intake manifold, the combination of fuel supply means including a fuel conduit through which liquid fuel flows to the engine, and a cooling tube portion within the conduit and extending longitudinally of 2,963,013 Y Y f' the conduit and having an open end directed into the ow of liquid fuel to the engine and the other end of said tube connected to said intake manifold so that the fuel flows into the tube portion and vaporizes therein to cool the tube portion and the remainder of the fuel flowing to the engine.

6. In a fuel supply system` for an internal combustion engine having an intake manifold, the combination of fuel supply means including a fuel conduit through which liquid fuel flows to the engine and having a portion of enlarged inside diameter, and a cooling tube having a convolute portion of smaller diameter contained within said enlarged portion and having a terminal portion with an open end directed into the flow of liquid fuel to the engine, means adapted to connect to the other end of said tube to said intake manifold whereby fuel flows intol the tube and vaporizes therein to cool the tube and the remainder of the fuel flowing to the engine.

7. In a fuel supply system for an internal combustion engine having a fuel intake manifold, the combination of fuel supply means including a fuel conduit through which liquid fuel flows to the engine, a cooling tube contained within said conduit and being open to said conduit, and means connecting said cooling tube to said manifold whereby liquid fuel is drawn into said tube and vaporizes therein to cool the tube and the remainder of the fuel flowing to the engine.

8. ln a fuelsupply system for an internal combustionA engine having a fuel intake manifold, the combination of fuel supply means including a fuel conduit through which liquid fuel flows to the engine, a cooling tube contained within said conduit and being open to said conduit, means connecting said cooling tube to said manifold whereby liquid fuel is drawn into said tube and vaporizes therein to cool the tube and the remainder of4 the fuel flowing to the engine, and thermostatic means adapted to close said connecting means between said manifold and tube at relatively low engine temperature and adapted to progressively open said connection means as the engine temperature increases.

9. A cooling device for a liquid fuel supply system having a source of vacuum connected thereto comprising a casing portion having a longitudinally extending fuel passage therethrough and a fuel inlet port for said passage, and an evaporating coil disposed within the fuel passage and having a small diameter bore open at one end to receive fuel from the passage so as to be effected to evaporate therein a portion of the liquid fuel owing through the passage and thereby lower the temperature of the remainder of the fuel passing through the passage and means adapted to connect said tube to said vacuum source and a thermostatic means affected by the engine temperature and located adjacent to the open end of the said evaporating coil and built into said casing portion at said fuel inlet port effective to reduce the flow of fuel through the evaporating coil by obstructing said open end of said coil at relatively low engine temperature and progressively opening said open end as the engine temperature rises.

References Cited in the file of this patent UNITED STATES PATENTS 2,191,490 Mitterer Feb. 27, 1940 2,773,492 Klemm Dec. 11, 1956 2,791,186 Alden May 7, 1957 FOREIGN PATENTS 703,244 Germany Mar. 4, 1941 

